364 JOURNAL OF COSMETIC SCIENCE a) ........... b) .. .. Figure 16. SEM observations of longitudinal and cross sections of hair fibers before (a,c) and after (b,d) MA/BOE treatment. The hair fiber was treated for one hour at 25øC. o a) b) Figure 17. Variation of moisture content in hair fiber (a) before and (b) after MA/BOE treatment. The hair fiber was treated for one hour at 25øC. Furthermore, the amount of agents (MA and BOE) that penetrated the hair was more than 10 wt%. The authors consider that the aqueous molecule is replaced by MA and BOE after the treatment, and that therefore the hair fiber treated with MA/BOE solution prevents the change in moisture content during the blow-drying process.

LIGHT SCATTERING IN HAIR CUTICLES 365 a) Figure 18. Mean total number of cuticle layers before and after cleansing/combing cycle. In order to evaluate the protection effect of the MA/BOE against damage to the cuticle, a decrease in the number of the cells was counted after 150 times through the hair care cycle: shampooing/rinsing/blow-drying with combing. Figure 18 shows the comparison of the mean total number of cuticle layers before and after hair care cycles. The lack of cuticle layers was confirmed in fibers both with and without MA/BOE treatment during the cycles, but the fracture of cuticle layers was suppressed by MA/BOE treatment. It can be said, therefore, that MA/BOE treatment is effective both for developing hair shine and for protection from cuticle damage by the blow-drying/combing process. ACKNOWLEDGMENTS The authors are grateful to Dr. Tatsushi Wakisaka, Mr. Yoshikazu Ohtsuka, and Ms. Yoshiko Chikawa of the Analytical Research Center, Kao Corporation, for their technical assistance and helpful discussions. The authors also thank Mr. Itomi Homma, Director of Hair-Care Laboratories, and Dr. Koichi Nakamura of Hair-Care Laboratories, Kao Corporation, for helpful discussions and guidance. REFERENCES (1) S. Nagase, S. Shibuichi, M. Ohshika, M. Okamoto, Y. Masukawa, A. Mamada, and N. Satoh, Light- scattering control at medulla enhances human hair shine, Proceedings of the 21st IFSCC International Congress 2000, Berlin, 153-159 (2000), and references therein. (2) S. Nagase, S. Shibuichi, K. Ando, E. Kariya, M. Okamoto, A. Mamada, and N. Satoh, Structure factors of hair fiber influencing beautiful appearance of hair, Proceedings of the 21st IFSCC International Congress 2000, Berlin (2000). (3) M. Okamoto, A. Mamada, R. Yakawa, S. Inoue, S. Nagase, S. Shibuichi, and N. Satoh, Hole generation mechanisms in hair medulla and its repairing technique, Proceedings of the 21st IFSCC International Congress 2000, Berlin (2000). (4) S. Nagase, S. Shibuichi, K. Ando, E. Kariya, and N. Satoh, Influence of internal structures of hair fiber